A few months ago a paper appeared online that argued, among other things, that octopuses might have arrived from space several hundred million years ago as frozen eggs, carried by a meteorite. The paper has 33 authors and is in press in a journal called Progress in Biophysics and Molecular Biology. Much of the article is concerned with an older idea that all life on Earth might have been seeded from space, but it is the octopus claim that has been picked up by the media. Several news stories* have also made a connection between this article and my book Other Minds, where I claim that because of their combination of behavioral complexity and evolutionary distance from us, encountering a cephalopod like an octopus is probably the closest we will come to meeting an intelligent alien.

Might octopuses really have come from space? Is this a possibility to take at least somewhat seriously? I don’t think it should be taken seriously at all; it is vanishingly unlikely to be true.

A number of people have said, mostly fairly politely, that they think the idea is crazy, but they’ve not said why it’s crazy. One person said that “no evidence” had been presented for the claim, which makes it sound like a possibility that cannot yet be ruled in or out. A social media mention appealed to Occam’s Razor, the idea that we should prefer simpler to complex hypotheses when we can. But we ought to be be able to do better than this (especially as I think that “Occamist” arguments are usually weak). So why do I write the idea off rather than taking it seriously?

The octopus-from-space paper cites a 2015 paper that reported the first sequencing of an octopus genome, by Caroline Albertin and coauthors. This 2015 study is used, along with others, to suggest that octopuses have genetic features that are so unusual that they support unorthodox ideas about their origin. But a look at the Albertin paper shows, instead, that octopuses sit very comfortably with their apparent animal relatives on Earth, rather than being additions from somewhere else. Here is one paragraph (of many with similar implications) from the paper:

In gene family content, domain architecture and exon–intron structure, the octopus genome broadly resembles that of the limpet Lottia gigantea, the polychaete annelid Capitella teleta and the cephalochordate Branchiostoma floridae…. Relative to these invertebrate bilaterians, we found a fairly standard set of developmentally important transcription factors and signalling pathway genes, suggesting that the evolution of the cephalopod body plan did not require extreme expansions of these ‘toolkit’ genes….

Some of the language here is technical, but the basic ideas are simple. Octopuses have fairly similiar collections of genes to limpets (those flat shellfish that stick tightly to rocks), to a marine worm (annelids are the group that includes earthworms), and a lancelet (a silvery fish-like sliver of an animal that is a fair bit closer to us). Barring the most freakish improbabilities, there is no way an animal living on another world could end up with such a similar set of genes to animals here on Earth, such that when it came here frozen in an asteroid, it would have all sorts of apparent relatives among limpets and worms.

In some ways there’s no reason to expect that aliens would have a genetic system similar to ours at all (with DNA and RNA and all the rest), but setting that aside, if octopuses are insertions from another world, they should not look like genetic cousins of limpets and worms. The octopus does have genetic quirks, but these fit in as quirks of an unusual animal with a rich set of geneaological relationships to other animals around us here.** The genetic evidence leaves no real doubt that octopuses evolved on Earth. They are like aliens but they are not really aliens.

Do I think this paper should not have been published? In general I am very reluctant to say things like this – I think it’s fine for all sorts of weird and controversial ideas to get published and discussed. But in this case, I do think there was a sort of breakdown, and the paper ought not to have been published in the form it has. The journal is an “Elsevier” journal, in a range alongside a lot of prestigious ones, and the newspaper articles that have picked it up say things like this: “Octopuses are aliens. That’s the claim being made by a team of 33 researchers published in a peer-reviewed scientific journal.” In a journal with that title and the characteristic Elsevier presentation, the usual expectation would be that the paper will have been refereed (peer-reviewed) and assessed in the usual way, and here something does seem to have gone wrong. If the reviewers of the paper included any kind of zoologist, they’d immediately point out what I say above about octopus genetics, and that should have been the end of it, at least for that part of the paper. To publish it anyway makes genetic evidence about evolution and the history of life look softer and less informative than it really is.

** Albertin et al. again: “statistical analysis of protein domain distributions across animal genomes did identify several notable gene family expansions in octopus, including protocadherins, C2H2 zinc-finger proteins (C2H2 ZNFs), interleukin-17-like genes (IL17-like), G-proteincoupled receptors (GPCRs), chitinases and sialins….” ”Our analysis suggests that substantial expansion of a handful of gene families, along with extensive remodelling of genome linkage and repetitive content, played a critical role in the evolution of cephalopod morphological innovations, including their large and complex nervous systems.”

*** The paper has various other problems on the zoological side. It says: ”The genome of the Octopus shows a staggering level of complexity with 33,000 protein-coding genes more than is present in Homo sapiens (Albertin et al., 2015).” This is an error, though perhaps a typo or poor piece of expression. An octopus does not have 33k more genes than us; it has 33k protein-coding genes, which is probably more than us.

More importantly, it includes this passage:

The transformative genes leading from the consensus ancestral Nautilus (e.g. Nautilus pompilius) to the common Cuttlefish (Sepia officinalis) to Squid (Loligo vulgaris) to the common Octopus (Octopus vulgaris…) are not easily to be found in any pre-existing life form….

The nautilus is not a likely ancestor of octopuses, and there is certainly no line of descent from nautilus to cuttlefish to squid to octopus. Those last three – cuttlefish, squid, and octopus – are all present-day animals who share common ancestors, with squid and cuttlefish sharing a more recent common ancestor than squid and octopus. For what is known about cephalopod origins and these relationships, see this paper by Björn Kroger and coauthors.

The photos in this post are a chronological sequence taken at Octlantis.

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The purple beast, perhaps 5 or 7 mm long, is Flabellina rubrolineata, a nudibranch. It reminds me of the mythical Hydra. This post is photographic, breaking up some wordy and weightier ones about Peter Singer’s book Animal Liberation. In the photos below, the mythical Hydra will feast upon a non-mythical Hydroid.*

First, seize your hydroid.

A hydroid of this kind looks like a flower on a long stalk, but it is an animal – a cnidarian, related to corals and jellyfish.

The flabellina wraps its mouth parts around it.

And soon…

… the flower-like part is consumed,

… leaving only the stalk.

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Notes:

The previous post included a note about the ever-increasing pressure on Australia to end its indefensible “live export” trade, in which thousands of sheep and cattle are crammed into stifling ships to be shipped to the middle east or Asia to be slaughtered using primitive methods, if they survive the hell of the trip, on site. Pressure has continued to mount on the federal government, and the opposition Labor party has pledged to end the live sheep trade, at least, if it wins government. This is a small but real piece of good news. A recent poll also found that about three quarters of Australians, including a strong majority in rural areas, want live export to end. What some politicians appear not to realize is that this is not, for a lot of people, a minor question that will fade on election day when put alongside economic issues. Instead, it is an ongoing and undeniable source of shame for the country – no small matter for many voters.

Update May 18: A columnist in the Sydney Morning Herald, David Crowe, writingagainst an immediate end to live exports, says this: “Farmers who sell sheep for live export might get about $130 per head for an animal that has already produced wool for about five years. This could be $20 more than selling mutton on the local market.” These sheep are put through their nightmare for an extra $20? I can hardly believe it. And I can hardly believe that Crowe noted this fact to argue for a continuation of the trade.

* A non-mythical Hydra is also a hydrozoan, perhaps from the same group – I am not sure – as the hydroid consumed by the flabellina. I think the hydroid above might, along with non-mythical Hydra, be in the Anthoathecata. Guidance would be welcome (Eudendrium)? The hydroid is colonial. A helpful figure is here.

Above is a Banded Coral Shrimp, Stenopus hispidis, in one of several hundred flawed photos I’ve taken of this species over recent months. I’ve become interested in these animals and want to get a good shot, but part of what makes them interesting makes them hard to photograph. They are very active, with arms and feelers moving continually, so a fast shutter is needed. But those arms and feelers extend through space, forward and back; they very much occupy their dens, filling them with appendages, so the focus has to reach pretty deep. They like dark spaces, too, and have some near-transparent parts. All this, together with my preference for simple gear, makes them quite a challenge. I have countless photos with one problem or another.

The phrase in my title was used by Peter Singer in his 1975 book Animal Liberation, in an attempt to say where a line might be drawn between animals we should not eat (when we have other good options) because they can probably feel pain and hence deserve some moral consideration, and animals that probably can’t feel pain and don’t have interests of the kind we need worry about. He said that somewhere between a shrimp and an oyster is “as good a place to draw the line as any.”

I am currently reading the most recent edition – the 40th anniversary edition – of Singer’s book. I’d read some, but not all, of the 1975 edition a long time ago. I’m finding the power of the book extraordinary, even after all these years of debate. The book has been updated, especially in its examples, but the basic ideas are familiar and have been assessed countless times. Yet still, in some passages, reading the book feels like being run over by a truck.

Singer takes a “utilitarian” approach to moral issues, emphasizing especially the avoidance of needless suffering. A lot then depends on who can suffer and who, in principle, cannot. A conference at NYU last year, especially the session I was part of, made some of these questions seem especially difficult. I and a few others gave talks trying to get a handle on the most basic kinds of experience, especially in invertebrates like crabs, bees, worms, and octopuses. Singer was there, and at one point in response to discussion he indicated his phrase from Animal Liberation as an attempt to mark a reasonable border. We’d probably be OK if we did not concern ourselves with the welfare of oysters, but it would probably not be OK to completely ignore the welfare of a shrimp.

In later editions of the book, including the one I’m reading, he was more even cautious – we don’t know what’s going on inside an oyster, so it’s better not to eat them. In an email quoted by Christopher Cox in Slate in 2010, he was closer to the 1975 view – ”while you could give them the benefit of the doubt, you could also say that unless some new evidence of a capacity for pain emerges, the doubt is so slight that there is no good reason for avoiding eating sustainably produced oysters.”

Suppose we assume, for discussion, a moral outlook like Singer’s. In the light of what we know now, how reasonable is that handling of the border? It looks pretty good, I think. The term “between…” has problems with it, which I’ll get to some time. But let’s set that aside and look first at the oyster/shrimp contrast.

Shrimp are arthropods, along with insects, spiders, centipedes, and the like. Among arthropods, shrimp and some other crustaceans are starting to look quite special.* Those banded shrimp in the photos, for example, seem to have quite a lot going on inside them. If you’re careful with them, while diving, they will often come out and inspect you. This species is a symbiotic cleaner of larger animals – fish, eels, even turtles – so they are oriented towards useful but precarious relationships with others. They are monogamous and territorial. Here’s a bad photo of a pair interacting. (The one on the left is mostly upside down.)

Not all shrimp live like this (and the “shrimp” above are really closer to lobsters in evolutionary terms). What is important in this context is not anecdotes but some recent experimental work, especially by Robert Elwood. Elwood has shown that although crustaceans like shrimp and crabs have fairly small nervous systems, the evidence for pain in these animals is surprisingly strong. Shrimp will groom and tend wounded areas, and those behaviors are reduced by local anaesthetics. Hermit crabs will abandon shells in response to electric shocks, but do so in a way that trades off, in quite a sophisticated way, quality of shell with strength of shock. The evidence for pain in crustaceans is good, and much better than the evidence for pain in insects.

An oyster, in contrast, has a very small and decentralized nervous system. Whereas recent evidence pushes quite hard in the direction of recognizing crustacean pain, there is no such evidence I can find for oysters. It’s difficult, though, to find any work in recent years on oyster behavior. One reason is that even compared to other shellfish, such as clams and scallops, there is not much that oysters can do. Clams can dig and scallops can swim. Scallops and some clams have genuine eyes. Oysters may have some light-sensitivity, despite lacking eyes, and they have tiny ‘tentacles’ that are sensitive to various things. But their behavioral responses, as adults in shells, are very limited.† An oyster will not swim up towards you like a castanet, as a scallop can. As far as I can work out, oysters can do little more than open and close their shell, and make other adjustments to the flow of water they bring in. Their reproductive behaviors are simple, too. It is always possible to imagine a very simple system having rich experiences like pain – and imagine any very complex organism lacking them – but those acts of imagination are not evidence for much. There seems no role for pain in an oyster’s life – in the way there is for shrimp and crabs, as Elwood emphasizes.

Is it likely then that experience is at zero in an oyster? There is absolutely nothing it feels like to be one? One reason I hesitate about this brings in another theme discussed at the NYU conference, something I am thinking about a lot at the moment. A mistake we might make in this area is to think too much in terms of dichotomous, presence-versus-absence views of subjective experience. That might be a mistake, at least when thinking about animals. Instead, the presence of experience itself might be a more matter of degree.

Some ways in which there could be a gradient here are not hard to think about – you might think experience is either present or absent, and within cases where it’s present, there is a more-versus-less question with respect to intensity, complexity, or something like that. The more difficult options are those that challenge this way of thinking about the “low end” of the scale, and do so without falling into panpsychism. We might say: within simpler animals, some have internal goings-on that are more experiential, more experience-like, but there is no point at which this special thing – subjective experience – is suddenly present. It is hard enough to even roughly mark out this option, let alone develop or defend it. (At the NYU conference, Michael Tye argued that the options I am gesturing towards here are not possible at all.) All this would make it harder to work out what to say about the oyster, though perhaps it doesn’t make it harder to work out what to say about oyster pain. Some forms of proto-experience might not include a relevant analogue of pain.

In any case, in Singer’s shrimp (and other crustaceans), recent work has shown surprising complexity that is directly relevant to questions about pain. In oysters, not so. Shrimp are pretty clearly in the category where it at least makes sense to consider their subjective well-being, and oysters most likely are not (give or take the questions just above). Shrimp and oysters might also be special within their respective groups – crustaceans are better candidates for feeling pain than other arthropods, at least at the moment, and oysters are behaviorally simpler than other molluscs, even other bivalves. The area “between” shrimp and oysters is where the harder cases are, and not too many animals in that area are important as human food sources.

For me, the material above does not yet settle the question of what it’s OK to eat; it does not settle what relations we should have to animal lives and deaths. And while these questions about boderline cases are interesting, they are not nearly as pressing as questions about animals that are not borderline cases, like cows, chickens, and sheep.†† After I work through the last part of Singer’s book, I am going to grapple with those questions next.

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Notes:

* The animals called “shrimp” form a non-monophyletic group (they do not comprise a single branch of the phylogenetic tree, but are collected from different nearby branches). The same applies to crustaceans. I am not going to worry about this, though it could matter if neural evolution went very differently on different branches that yielded animals we call “shrimp.” This Wikipedia entry is helpful. The banded shrimp in my photos are in the Stenopodidea, closer to lobsters and crabs than to other “shrimp.”

† An obvious experiment worth doing with oysters would be a classical (Pavlovian) conditioning experiment. Classical conditioning is very widespread in animals, including other mollusks (gastropods, cephalopods). There is even a report in an anemone. I can’t see a record online of someone attempting this experiment with an oyster, but it ought to be straightforward. One would pair some initially neutral (but perceptible) stimulus X with some other stimulus Y that causes the oyster to close its shell. The aim is to see whether the oyster learns to close the shell in response to X, because of its predictive relationship with Y. Choosing a suitable X might be the hard part.

†† An especially pressing question in Australia at the moment is the continuation of the truly nightmarish “live export” trade, in which thousands of animals are crammed into stifling ships to be shipped to the middle east to be slaughtered, if they survive the trip, on site. The latest horrors, revealed a week or so ago by Animals Australia, may be turning the tide of opinion at last.

Update: The Guardian has been excellent in its coverage of the recent (2018) live export scandals. Reverse chronologically, some good articles are here, here, here, and here.

A week ago, in the late afternoon, I got into the water at a site I’ve dived hundreds of times now – Cabbage Tree Bay, just north of Sydney. The conditions looked OK from up top, but there was a strong surge below, with volumes of water chugging steadily in and out, carried by a cyclone swell coming in from the Pacific. Everyone down there was collected together in a regular forward-and-back motion, on a rhythm of eight to ten seconds or so.

I’d gone into the water to visit some giant cuttlefish (Sepia apama) I’d dived with a few days before. One was extremely bright and colorful; the other was more muted in color, large and notably fat. This second one, who also made slow motions with his arms, I thought of as “The Elephant” – an elephant with eight trunks. The bright one, who I’d seen just once previously, has no name yet.

The cuttlefish were both in dens, about 100 meters apart. I went to and fro between them. The Elephant often lay flat on the bottom; the other was in continual motion. He was carried on the surge, along with me and the larger fish, in a closely synchronized dance, forward and back.

Over ten years ago now, I first got into this water and come across these animals. I was mesmerized by their colors, as described in the first pages of Other Minds. These animals can change their entire color in less than a second, moving between complicated patterns and solid washes of color. Their faces glow with electrified threads, replaced by periodic dark clouds and flares of bright yellow. And an endless range of reds: brick, magenta, cadmium red. Every possible red.

In the same waters after starting to visit the cuttlefish, I soon came across octopuses, especially Sydney’s “Gloomy” octopus. These animals are much smaller than the cuttlefish, with bodies occasionally up to a rugby ball’s size, but usually smaller. They have large eyes (hence the name) and they also change color. One of the very first octopuses I saw in these waters did something I still find puzzling. It was hunting, leapt upon a hermit crab in its shell, and carried the shell back to its den. Then it did not try to eat the crab, but positioned the shell at edge of its collected pile of objects, with the open end outwards, in what looked like a quite deliberate way. The crab found itself held outwards. Events like those were the beginning of my fascination with these animals. After I began to watch them, I began reading about their history and biology, especially their evolutionary relationships to vertebrate animals like ourselves. Cephalopods, as molluscs, are more closely related to oysters than to fish or to us. The evolutionary branching that separates their line from ours lies so far back that I came to think of them as an “independent experiment” in the evolution of behavioral complexity, and probably in the evolution of experience itself.

In front of The Elephant was a dull shell. I suspected a hermit crab was hiding inside, and sure enough there was. Soon he or she began to eat (hermit crabs have spectacularly bad table manners), roamed around a bit, and fossicked, all in front of the Elephant’s face. I guess giant cuttlefish are not predators of hermits; the crab was not scooped up and brought into the den like the one a decade or so earlier. At one point the hermit stopped messing around and stood, with eyes out on stalks, right in front of the cuttlefish and stared at him. There we were: me at the back, a hermit between us, and a giant cuttlefish being inspected by both.

The water was full of silt and a bit dark – no good for photography. I was partly glad about that, as it reduced distraction. And although these animals did not do much while I was down there, the bright one and the Elephant, in the end I realized I was there with them for over 90 minutes, just hanging out, drifting forwards and back, until my air ran down and I swam in.

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Feb 23, 2018. All the images in this post are photos of the “bright” unnamed cuttlefish, taken a few days earlier. So these are all photos of the same animal, on the same dive. All were taken with the available light, no flash. Here is a photo of The Elephant, taken on the murkier day of the post, and here is Elephant plus Hermit.

After my accidental introduction to skeleton shrimp, I went back to Nelson Bay to look for them – to look for something I can hardly see, except as a translucent scrap. My approach was to look for motion at the right scale – they move a lot, in a vigorous bobbing manner – take some photos, and later see how I did. The surprise that came out of this is that skeleton shrimp were just about everywhere, on those dives. Once I found one in a photo, I’d find others lurking around it – crouching, interacting, clambering about. Attempts to get a portrait, however, were not very successful. Above is one leaning forward like a praying mantis, to whom they are often compared. Below is a shot that would have been good if the animal had not been hanging upside down and facing away. I became curious, though, about what the sequence of shots that included this animal showed next.

He twisted himself into one of the strange shapes these animals favor.

And then: what is the other animal, which looks like a smaller skeleton shrimp, doing on the right?

At least some species of these animals have much smaller females than males, and the second animal looks like a female, from the figures I’ve seen on the web. That raises the possibility of a mating. But those globules on the male that the smaller one is attending to are, I think, gills rather than sex organs. So I don’t know what went on between these two skeletons. Below is the aftermath of the kiss-on-the-gills (and the close view shows a jumble of other limbs of these, or similar, arthropods, all over the scene).

I took some nudibranch photos on those dives as well, and in many cases I saw later that, around the focal slug, there were skeleton shrimp in a little horde in the background.

Above is a Dermatobranchus primus (I think), with a skeleton looking over his+her shoulder. Below is Verconia alboannulata, haunted from above.

All this was also a reminder of the ecological success of arthropods. On land, insects are everywhere. In the sea, they are not quite so obvious, but can often be seen – I now realize – if you look closely.

2. This week saw the release of an open letter, that I signed, about the treatment of some other arthropods – lobsters and crabs – in restaurants and shops in the UK. The letter was organized by Crustacean Compassion. The aim is not to prevent crustaceans from being eaten at all, but to introduce consideration of their welfare into their handling and killing. The boiling alive of lobsters and crabs is a central example of what should end. The arguments behind the letter (which are outlined well in this briefing) center on the now strong evidence that at least some crustaceans can feel pain. Robert Elwood has been a leader in these developments. I discuss his work in chapter 4 of Other Minds.

A few years ago I headed a post with a photo by David Liittschwager, showing all the life teeming in a tiny scoop of sea water. I was reminded of the shot during some time spent recently with the object above, which is a bryozoan colony. I looked at it initially because Tom Davis, a biologist who was showing me around part of the Fly Point dive site in Nelson Bay, picked it out to me. On its stems were tiny sea slugs, each no more than a couple of millimeters long. (Tom has evidently had microscopes implanted in his eyes.) I took some photos.

Bryozoans are animals I’ve not written about before. They are from the “bilaterian” part of the tree of animal life – their bodies have left-right symmetry, as we do. (They are “lophotrochozoans,” not far from molluscs and annelid worms.) But bryozoans turned away from the evolutionary paths usually associated with animals of that kind, and began to live more like plants. It’s tempting to say they went back to living like plants, but plants themselves, of the familiar kind, are not especially old organisms and are not in any bryozoan’s history. Lots of living things have discovered, in evolution, a tree-like branching shape, including corals and various seaweeds. But bryozoans are quite a long way away, evolutionarily speaking, from other organisms with that sort of design, and they made the plant-like turn in a very concerted manner; many of them look just like underwater bushes or mosses. Almost all live in colonies – above, you’re looking at a very large number of these animals, not at one.

Later, on the computer, I located the tiny nudibranchs. Here is one. It is Okenia harastii, named after Dave Harasti, another Nelson Bay biologist and diver.

(You can’t find this Okenia in the shot at the top; that is just a shot of the Jackson-Pollock-like bryozoic mass.)

I looked through the branches of the bryozoan, reflecting on how bush-like it was. Then I saw a tiny stripe of of red. I zoomed in further, and realized the stripe was on a talon-like claw. The claw was attached to what initially looked like another stem of the bush, but that “stem” was attached to another one with a conspicuous hinge. I was not looking at more of the bryozoan colony, but at an arthropod called a skeleton shrimp.

That is not a very good photo, but I had no idea the animal was there.

Soon we found another of these, and a third:*

Skeleton shrimp are not really shrimp, but a kind of amphipod, with two sets of those talon-like claws. Flipping through the photos showed that they are in constant motion.

Below is a zoomed-out shot that shows the location of three we found. The larger one (third photo above) is at the lower right and the smaller one (photo just above) is near the center. (A higher-res version of the photo below is here.) I am going to go back to the site and (somehow) get a skeleton shrimp portrait.

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Notes:

* My wife found two of these, as she worked out that flipping through the photos revealed them, given that they were the only things that moved across flips.

This is a good site about the bryozoan, which is probably Zoobotryon verticillatum.

David Liittschwager also did the photos for Olivia Judson’s octopus feature in National Geographic a little while back. There are a lot of good wildlife photographers, but I think Liittschwager’s work is special. Thanks again to him for permission to use his seawater photo on my site.

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What do we have here? Various bits of body – some lobster, I think, on the left; a clam shell; a bit of crab claw and crab carapace. Arrayed in the front are what look like the remains of barnacles (not usually octopus food), some fishing line, scraps of algae. And in the middle above the barnacles, held there by the octopus, a black object that looks like an old bit of wood.

The octopus was at Chowder Bay, a great place for collecting, if you are an octopus. I’ve been reminded of dens like this during some discussions of octopus behavior that came out of the recent paper about our “Octlantis” site. At least much of what we’re seeing at a den is a fortuitous result of the octopus’ eating habits. They collect food, bring it home to eat, and leave the remains lying around. But they often then arrange and rearrange the debris around their dens, and often also collect and arrange objects that are implausible options as food. To what extent is the creation and maintenance of dens like this a deliberate, intentional act by an octopus? What, if anything, are they trying to do?

We’ve just published another paper that explores these questions – it’s an invited “Addendum” to the previous paper, in a journal called Communicative and Integrative Biology.* Marty Hing and I also recently wrote a more popular piece along similar lines for The Conversation. Some difficult questions have been unearthed by all this, including some that we wrestled with in emails but could not cover in the articles. I’ll follow them up in a couple of posts here.

One important concept in this area is that of an intentional action. A lot of the questions surrounding these behaviors can be expressed by asking: which features of octopus dens, and the high-density sites that have many dens, are produced intentionally, and which are accidental or fortuitous?

Several different senses of “intentional” are relevant. In one usage, the term is roughly synonymous with “purposeful” or “on purpose.” In a second sense, “intentional” actions are those that result from an animal’s beliefs and desires.** (A third sense, not so obviously relevant, is seen in recent discussion of a particular kind of communication, called “intentional” communication. In this kind of communication, seen certainly in humans and apparently in some other animals, a speaker or signaler tries to get something across, rather than just producing a signal automatically.)

What I am after is mostly a contrast between intended and inadventent effects – intended effects are achieved “on purpose.” That is the first sense above. You might think the first two senses are very close – isn’t a purposeful action one that reflects an animal’s wants and desires? Perhaps not. There can be purposes present in the actions of an animal, or other organism, that are not appreciated by the organism and not psychologically registered by it. There is a sort of purpose seen in the way some plants track the sun, also in the way you blink when something gets close to your eye, and the mechanisms that make these things happen apparently don’t involve beliefs.

There is a lot about this in Dan Dennett‘s new book From Bacteria to Bach and Back. He refers to the purposes of behaviors that are unappreciated by the animals themselves as “free-floating rationales.” I’ve never liked this phrase, as it suggests a behavior that simply “makes sense” for an animal, whether or not the behavior is produced because it makes sense. An octopus might bring scallops home to eat, and the shells might then make it easier to maintain a den, but the bringing-home behavior might be done purely because eating is safer at home, so the consequences for den-building are fortuitous byproducts. I think that Dennett does not mean his free-floating rationales to float as freely as this, but his term does suggest it. Here is how I would set things up.

The behaviors of animals and other organisms arise through many different internal mechanisms, and these behaviors can be shaped by feedback of various kinds. In different ways, there are effects of a behavior that have consequences for the future production of that behavior, or its ongoing course. A behavior’s effects may lead to the behavior ceasing, continuing, changing, or being repeated. In some cases this feedback work via evolution itself. A particular behavior may lead to the animal surviving and reproducing, or not. When behavioral tendencies are inherited, some may be retained over generations due to their consequences, while others are lost. There is no need for intention in those cases, but there is a feedback-relevant effect of the behavior. In the positive cases, where the feedback makes the behavior more likely to be produced, this is something like a goal.

In other cases a behavior occurs, has effects, and the effects have consequences bearing on that behavior that go via the animal’s own senses, nervous system, and decisions. In some cases this might be simple in ways that resemble the operation of a guided missile – there is a control system that tracks whether the animal is taking a certain course, and makes small adjustments in response. In more complicated case, the animal is responsive to the effects of its actions in a richer way – if one action fails to have a particular effect, as registered by the animal, another action is tried. And when a specific outcome is registered, the attempts and modifications cease. In the most complicated cases of all, the animal has an intention in mind – I want to get to the gym – and moment-to-moment decisions are taken that make that outcome as likely as possible.

Something in common across all these cases is sensitivity to feedback, and that is what produces a kind of targeting of a behavior on a particular outcome, whether this is an intended outcome or one that figures in feedback of another kind. There are two extreme cases or poles – one where an outcome is held consciously in mind, and one where only a long causal chain that extends over generations aligns a behavior with a goal. Between those poles are a lot of partial cases, including, most likely, the behaviors of our octopuses, and I’ll grapple with those in detail another time.

The last shot here is a Bullina lineata, a “bubble shell” at Nelson Bay. Appropriately, they seem to become common right around Christmas.

An unexplained terrestrial incursion by several dozen octopuses, walking onto the shore in Wales a few weeks ago, reminded me of a plan to write something on this site about the relations between life on land and in the sea.

The early stages of animal evolution all took place in the sea. Animals began to come onto land something like 450 million years ago, in the Ordovician. Arthropods were the first, and different members of that group made their way onto land something like seven separate times. Vertebrates came later.

The photos in this post were taken last year at the Myall Lakes in Australia – a liminal, borderland place with respect to land and sea. A narrow isthmus separates the Pacific Ocean from a lake system fed by a small river. The water on the lake side is brackish, mixed with salt. The salt level fluctuates as the lakes are fed from one side with fresh water via the river from mountains inland, and from another side by ocean tides that travel miles up the lower Myall River from Port Stephens (just near the Nelson Bay dive sites). Myall Lakes is also the place where, just about 30 years ago, I overnight became an outdoors sort of person, having not been one before.

Earlier this year the biologist Geerat Vermeij published a short but very interesting paper about land and sea. The title is “How the Land Became the Locus of Major Evolutionary Innovations,” though the aim of the paper is more to show that that land did become such a locus, rather than to say a lot about how this happened. This a theme that Vermeij has thought about for quite a few years. The impression various people have had is that evolution had a natural early start in the sea, but once the land was colonized, evolution took off in a new way. It produced many more species, first of all, and Vermeij argues in this new paper that the land was also the site of many more “high-performance innovations” than the sea. He argues for this by listing twelve such innovations whose origin can be dated, and asking how many arose on land and how many in the sea. He only considers innovations appearing from the Ordovician onwards – he accepts that all the important early stages took place in the sea [1]. But from there, he says, most of the action took place on land.

Stretched out on the branch in the photo above is what looks like an Eastern Water Dragon. (These are all phone photos taken from a canoe.)Here is a closer look:

Of Vermeij’s twelve innovations, nine appeared first on land and later in the sea, one appeared at about the same time in both realms, and two have remained restricted to the land. Vermeij uses these cases to make a statistical argument; a “null hypothesis” would predict roughly equal numbers of land and sea origins, but significantly more first appeared on land [2].

I am not sure that the statistical test itself is very meaningful, as the twelve ”points” are not independent, but form packages to various degrees [3]. Some are also far more consequential than others [4]. But the statistical treatment is not needed to make the analysis interesting. A different problem is that although he’s talking about features that could, in principle, be found in both contexts (and most of them are), various of the features he discusses make much more sense in one context or the other, and specifically make more sense on land. I found myself thinking, as I read the paper, that he was not always being entirely “fair” to the peculiarities of life in the sea.

The most marked example among his twelve is “aerial locomotion,” or flight. Powered flight evolved at least four times in land, perhaps three times in marine animals (squid and fish), and the land animals did it about 90 million years sooner, despite the sea’s evolutionary head start. The reply I’d make is that all sorts of other marine animals are already flying, in a sense. On land, flight (along with burrowing, and some climbing) is the only way to escape the surface and move in a fully three-dimensional mode. In the sea, swimming and drifting lifts you up and away. Even before fish, jellyfish were flying. The value of motion through the air itself is surely much reduced in a marine environment.

Below is another water dragon (between the trunks), reflecting on land/sea questions.

Another example from Vermeij’s list is the dispersal of the sex cells, spores, and other “propagules” of one species by some different animal species. The role of bees in the pollination of plants, and the dispersal of seeds by putting them in edible fruits, are examples. This sort of thing, Vermeij says, is never seen in the sea. I am not sure about the significance of this one. Initially I thought: for the same reasons cited just above, why would a marine organism need help with dispersal of this kind, as gametes and other propagules can be so easily “broadcast” in the sea? Then I was reminded, in another paper by Vermeij and Grosberg, of the giant penises evolved by barnacles. These penises – up to the 8 times the animal’s length and hence the largest, proportionally speaking, in the world – enable a barnacle to reach a fair way out to its stationary neighbors to mate. Barnacles are not content with indiscriminate broadcast of their sex cells.

Some of Vermeij’s other cases seem “fairer” as land-sea comparisons. But I don’t yet buy the conclusion that conditions in the sea “constrain innovation” (as he puts it) more than conditions on land. A picture that suggests itself, not so different from what he says, places evolutionary innovations into a historical order in a particular way.

A number of huge, and necessarily early, innovations occurred in the sea – the evolution of animals and animal bodies, senses, limbs, and nervous systems. The sea is the natural context, as well as the actual one, for these sorts of stages. Life is harder on land, given the basic features of living systems. If you can make it there, many opportunities arise, but a different round of innovation is needed to enable such lives. It is not that the sea poses obstacles and constraints – and we have those early marine stages to thank for the brains through which these words are buzzing. But a move to land opens new, albeit difficult, doors.

[1] Vermeij: “Many innovations among multicellular organisms originated in the sea during or before the Cambrian, including predation and most of its variations, biomineralization, colonial or clonal growth, bioerosion, deposit feeding, bioturbation by animals, communication at a distance by vision and olfaction, photosymbiosis, chemosymbiosis, suspension feeding, osmotrophy, internal fertilization, jet propulsion, undulatory locomotion, and appendages for movement.” The list leaves out nervous systems, and perception (as opposed to communication) by means of vision.

[T]the innovation must have evolved more than once and in phylogenetically distant clades. I therefore excluded the turtle skeletal configuration in vertebrates, reduction and loss of digits and limbs in tetrapods, inflation in pufferfishes, the formation of varices and labral teeth in gastropods, shell loss in molluscs, novel respiratory structures in echinoids, opercula in bryozoans, insectivory in plants, wing articulation in insects, silk production in arthropods, constriction in snakes, the liana habit in plants, unidirectional air flow in diapsid tetrapods, the crab-like abdomen and sideways locomotion in crabs, and skeletal tube formation in bivalves, among others…

Of the 12 he includes, the first 9 are found in both contexts, but earlier on land, plant guards may have evolved in both contexts at a similar time, and the last two, animal-mediated gamete/propagule dispersal, and communal construction are (he says) only seen on land.

On the last, I may not entirely agree. If “communal” construction involves many individuals, then I don’t object, but if it is contrasted with individual construction, then the Sleeper Gobies whose burrows I mapped on my earlier website are an exception, as in these fish a pair of individuals works together to build the den. (Vermeij: “Marine animals in many clades individually construct and occupy shells, tubes, floats, mucus nests and houses, byssal enclosures, and burrows, but despite the complex behavior of many cephalopods, fishes, and marine tetrapods, communal building is unknown in the sea.”). I don’t count Octopolis or Octlantis as exceptions, by the way, and we have a new paper coming out on this question.

Here is the statistical claim: ”Compared with the null expectation that half of the innovations began or remained restricted to the sea and half did so on land, the observed land-first pattern is statistically significant, with a probability greater than 0.998 (binomial test).”

[4] For example: eusociality and communal nest building.

[5] For example: vascular anatomy in plants versus animals being recruited by plants as guards.

Last month our latest octopus paper appeared, describing a new site where octopuses live in unusually large numbers. We call the site, which was discovered last year, “Octlantis.” Soon after it appeared, the paper was picked up by the media, especially by popular science websites. Initially the stories were reasonably accurate, with just a little picturesque exaggeration, but some of them soon began to get out of hand. There are now articles about the site that claim the octopuses are “making art,” building “fences,” and engaging in a range of other behaviors that were not reported in anything we wrote. The episode has become interesting in itself, as it has gone beyond ordinary overstatement induced by the perennial charm of the octopus, and has become a snowballing or self-sustaining process, where the exaggerations in one story feed another story which embellishes things further, and so on.

(Above are two Octlantis octopuses, the second on the right).

The chain seems to have developed as follows. The University of Illinois at Chicago, where co-author Stephanie Chancellor studies, put out a press release. This was done well and has no exaggeration. It was picked up by Science Daily and other sites. Then Science did a story about the paper. Again the story was fine, but it used the crucial word “city” in the title: “Scientists discover an underwater city full of gloomy octopuses.”

“City” is not a word we’ve used, but it may well have come from our nickname for the site, “Octlantis” – perhaps too evocative a choice. In any case, that is when distortions began to appear. A profusion of articles appeared that not only used the word “city,” but described the site in a way apparently inspired by that word, with a range of behaviors that in some cases are embellishments of what we saw, and in some cases seem to have simply been imagined.*

A week or so ago I was sent some text by a radio station before an interview, and was startled to see how inaccurate it was. I asked how it was written, and was pointed towards a popular science website that they used as a source. So the write-up by the radio station was at least two steps away, probably three steps or more, from an actual reading of our paper, and each step seemed to have taken the “city” idea and run with it further.

This next shot is not from Octlantis, but from Nelson Bay, yesterday, where an octopus (of the same species) decided I’d come a little too close to its den:

We are presently writing a couple of follow-up pieces that clarify the situation, and also ask the question: which effects of octopus behavior seen at the Octlantis site are effects intended by the octopuses, and which are inadvertent? I’ll link to these when they appear. For now, though, we want to emphasize some basics, and try to prevent further flights of fancy.

Octlantis is not in any sense a city. It is not a cooperatively built and maintained structure, designed to allow many individuals to live in close quarters. It is an unusually dense collection of individual dens, most of them dug into a bed of scallop shells.

The shells are remains, we think, of scallops brought in by individual octopuses as food. The shells accumulate over time, and provide a better den-building material than the silty sand of the bay. As more shells are brought in, more octopuses can build viable dens at the site, and those bring in still more shells. There are a lot of fairly complicated behaviors at the site – lots of probing, displaying, and what often looks like a monitoring of who is around. We are presently trying to work out some of these behaviors. Octlantis is a remarkable site, but it’s not an octopus city.

_______________

Notes

* Here are some especially bad examples:

BigThink.com: “making art out of leftover shells, starting fights, tossing out roommates, and ignoring undesirable cohorts until they went away.”

Curiosity.com: “But when we say “city”, we mean “city”. Octlantians build their own structures from their leftovers, the shells of clams and scallops. They build fences to keep out their neighbors and protect themselves from the underwater elements under shell-tiled roofs.”

This is a higher-quality article. Fox News also did a story that’s not bad.

Newsweek‘s article is OK, and it ends (tempting more trouble perhaps) with a range of suggested names for the next sites found: “Octlanta, Octoville, Octopia, Octlahoma, Octopyongyang, Octomaha, Calamarimazoo (squids are not octopuses, but bear with us), Octorlando, Octokinawa, Oslopus, Octopeoria and Languedoctopus Rousillon.” I like the last one.

About eight years ago now, my friend Matt Lawrence discovered the site we call “Octopolis,” and since then it’s been an important part of my underwater explorations and a regular feature on this website. Octopolis, as the name suggests, is notable for its high density of octopuses – there can be up to 16 present in a small area, though more often it’s 5-6 or so. The occupied area is roughly centered on what looks like an old human-made object, perhaps dropped off a boat many years ago. This now-encrusted object, about a foot in diameter, provides a good den in a difficult environment for a couple of octopuses, given the silty sand of the bay and the abundance of predators.

Most of the octopuses at Octopolis live some distance from that object, on a bed of scallop shells. We think the initial object “seeded” the site by triggering a process of ecosystem engineering, in which octopuses living there bring in scallops whose shells provide den material for more octopuses, who bring in more scallops in turn…. Though most of the octopuses at Octopolis live on the shell bed, the role of that introduced object in initially altering a difficult environment always made the status of Octopolis slightly unclear.

But now we have a second site.

Last week a new paper appeared, describing an additional high-density site in the same rough area as the first. This site was discovered by chance by some friends, late last year. Clearly it needs an appropriate name, and we have settled on Octlantis.

This is another small area in which about a dozen octopuses can be present, many in dens just a foot or so away from each other – easily within arm’s reach. Like Octopolis, the crucial advantage it has over its surrounding is a probably its abundance of dens. Also as at Octopolis, thousands of scallop shells, probably left by octopuses themselves, provide building materials that make those dens possible. But an important feature of Octlantis is the fact that it was apparently not seeded by a human-made object. The site is centered on a small clump of exposed rocks. So Octlantis is entirely “natural” in its origins (though extensively octo-engineered since then – the term “natural” does not work too well in this context).

A version of the next photo appears as one of the figures in the article. Here two octopuses have set up on the side of one of Octlantis’ rocks. One has commandeered a beer bottle.

We’ve already seen a number of matings, fights, and other interesting behaviors at Octlantis. The paper includes some wild screenshots of evictions and conflicts. Here is a version of one (please excuse the weird colors).

Like Octopolis, Octlantis is full of other kinds of animal life as well. Once again we see the site frequented by large Wobbegongs (carpet sharks). This last photo shows one cruising ominously in.